Synthesis and 19F NMR study of RF-oleic acid-F13

A seven-step synthesis of Z-13,13,14,14,15,15,16,16,17,17,18,18,18-tridecafluoro-octadec-9-enoic acid (oleic acid-F13) is reported. The key step is a Wittig reaction to form the C9–C10 double bond with a Z:E isomeric ratio greater than 20:1. The 19F nuclear magnetic resonance (NMR) spectrum is included and unambiguous assignments have been made with the aid of 19F–19F correlation NMR spectroscopy (COSY spectra).